摘要:

1. Moths (Lepidoptera) are the major nocturnal pollinators of flowers. However, their importance and contribution to the provision of pollination ecosystem services may have been under‐appreciated. Evidence was identified that moths are important pollinators of a diverse range of plant species in diverse ecosystems across the world.2. Moth populations are known to be undergoing significant declines in severalEuropean countries. Among the potential drivers of this decline is increasing light pollution. The known and possible effects of artificial night lighting upon moths were reviewed, and suggest how artificial night lighting might in turn affect the provision of pollination by moths. The need for studies of the effects of artificial night lighting upon whole communities of moths was highlighted.3. An ecological network approach is one valuable method to consider the effects of artificial night lighting upon the provision of pollination by moths, as it provides useful insights into ecosystem functioning and stability, and may help elucidate the indirect effects of artificial light upon communities of moths and the plants they pollinate.4. It was concluded that nocturnal pollination is an ecosystem process that may potentially be disrupted by increasing light pollution, although the nature of this disruption remains to be teste

ISSN:0307-6946    

DOI:10.1111/een.12174

出版商:Blackwell Publishing Ltd    

年代:2015

数据来源: WILEY

摘要:

1. Wood decomposition in temperate forests is dominated by termites, fungi, and some species of ants and beetles. Outside of urban areas, temperate termite ecology is largely unknown, particularly when compared to tropical termites and other temperate organisms in the functional guild of wood‐decomposing animals.2. This review combines climate habitat modelling with knowledge of species physiology, behaviour, and community interactions to identify and prioritise future research on temperate termite ecology and biogeography.3. Using a correlative climate model, the regional distributions of three common temperate forest termite species are shown to correlate with different aspects of climate (e.g. mean versus minimum monthly temperature), but that overall their distributions within temperate systems correlate more strongly with temperature variables than with precipitation variables.4. Existing data are synthesised to outline how the subterranean, wood‐nesting behaviour of most temperate forest termite species links their activity to an additional set of non‐climate controls: wood type and tree species, soil depth, fungal activity, ant abundances and phenology, and competitive asymmetries among termite species.5. Although fine‐scale estimates of temperate termite abundances are rare, we provide upper bounds on their ecosystem impacts and illustrate how their regional abundances may influence forest structure and habitat availability for other organisms.6. This review highlights that rigorous ecological studies in non‐urban, intact ecosystems – with a particular focus on community interactions – are critically needed to accurately project future abundances, economic impacts, and ecosystem effects of temperat

ISSN:0307-6946    

DOI:10.1111/een.12185

出版商:Blackwell Publishing Ltd    

年代:2015

数据来源: WILEY

摘要:

1. Organisms can respond to changing climatic conditions in multiple ways including changes in phenology, body size or morphology, and range shifts. Understanding how developmental temperatures affect insect life‐history timing and morphology is crucial because body size and morphology affect multiple aspects of life history, including dispersal ability, whereas phenology can shape population performance and community interactions.2. It was experimentally assessed how developmental temperatures experienced by aquatic larvae affected survival, phenology, and adult morphology of dragonflies [Pachydiplax longipennis(Burmeister)]. Larvae were reared under three environmental temperatures: ambient, +2.5, and +5 °C, corresponding to temperature projections for our study area 50 and 100 years in the future, respectively. Experimental temperature treatments tracked naturally‐occurring variation.3. Clear effects of temperature were found in the rearing environment on survival and phenology: dragonflies reared at the highest temperatures had the lowest survival rates and emerged from the larval stage approximately 3 weeks earlier than animals reared at ambient temperatures. There was no effect of rearing temperature on overall body size. Although neither the relative wing nor thorax size was affected by warming, a non‐significant trend towards an interaction between sex and warming in relative thorax size suggests that males may be more sensitive to warming than females, a pattern that should be investigated further.4. Warming strongly affected survival in the larval stage and the phenology of adult emergence. Understanding how warming in the developmental environment affects later life‐history stages is critical to interpreting the consequences of warming for organism

ISSN:0307-6946    

DOI:10.1111/een.12175

出版商:Blackwell Publishing Ltd    

年代:2015

数据来源: WILEY

摘要:

1. Based on the slow‐growth high‐mortality (SGHM) hypothesis, which predicts that prolonged larval development increases mortality from their natural enemies, studies have often assumed that low quality of plants that slows larval development would function as a defence against insect herbivores. However, empirical support for theSGHMhypothesis has been limited, especially in natural and ecologically relevant contexts.2. In a leafminerAmauromyza flavifronsMeigen (Agromyzidae,Diptera), theSGHMhypothesis was tested along with four other hypotheses (e.g. prey size, mine appearance, density‐dependent parasitism, and plant quality hypotheses) to control for spurious associations between development time and parasitism that are primarily driven by other larval traits. Two host plant species,Saponaria officinalisandSilene latifolia, were grown under varying nitrogen levels, and leafminers developing on these plants were exposed to, or protected from, a natural assembly of parasitoids across the entire course of larval development.3. On both host plant species, leafminers that survived to an adult stage in the presence of parasitoids had a shorter development time than those in the absence of parasitoids, indicating that parasitoids disproportionately kill leafminers with longer larval development. The results provided concrete evidence for theSGHMhypothesis within the natural ecological context for these interacting species. Moreover, reduced plant quality was associated with higher larval mortality onSa. officinalisonly in the presence of parasitoids, suggesting that low quality could function as indirect plant resistance viaSGHMunder some tri‐trophic inter

ISSN:0307-6946    

DOI:10.1111/een.12177

出版商:Blackwell Publishing Ltd    

年代:2015

数据来源: WILEY

摘要:

1. Antagonistic interactions in herbivorous insects are often density‐dependent, so rates are predicted to vary dynamically over time as density changes. Fatal intraspecific interactions, especially cannibalism, occur between equal‐aged larvae in young first‐ and second‐instarSpodoptera frugiperda(J.E.Smith).2. A cannibalism experiment was conducted, starting with seven different densities of neonateS. frugiperdalarvae, each replicated 50 times. Larvae were examined daily for the duration of the first and second instars (7 days). Seven‐day mortality was density‐dependent.3. A stochastic mathematical model was developed in which per‐capita mortality from antagonistic interactions among equal‐aged larvae varies dynamically as density changes. A maximum likelihood method was developed to estimate the conditional per‐capita mortality rate from antagonistic interactions given an intraspecific encounter. An alternative model with mean‐mortality from antagonistic interactions that depends only on the initial larval density was also developed.4. The models were fitted to the experimental data, and compared using log‐likelihood. The dynamic model fitted the cannibalism data significantly better than the time‐averaged mortality model for all starting densities for the experimental data, implying that density‐dependent mortality varied dynamically over time even within short 7‐day periods.5. The conditional per‐capita mortality rate from antagonistic interactions was also density‐dependent, possibly because encounters became more aggregated at higher density, or because the probability that a larva died from the interaction was

ISSN:0307-6946    

DOI:10.1111/een.12178

出版商:Blackwell Publishing Ltd    

年代:2015

数据来源: WILEY

摘要:

1. Within the host range of herbivorous insects, performance hierarchies are often correlated with relatedness to a primary host plant, as plant traits are phylogenetically conserved. Therefore, it was hypothesised that differences in herbivore performance on closely related plant species are due to resistance traits that vary in magnitude, rather than in the nature of the traits.2. This hypothesis was tested by manipulating putative resistance traits of three congeneric thistle species (Cirsium arvense,Cirsium palustre, andCirsium vulgare) and assessing the performance of the oligophagous, leaf‐feeding beetle,Cassida rubiginosa. Measurements were done of survival, weight gain, and development time of the beetle on its primary host,C. arvense, and two alternative hosts under low and high nutrient availability, and on shaved and unshaved leaves.3. Survival ofC. rubiginosawas strongly dependent on plant species with final mean survival rates of 47%, 16%, and 8% onC. arvense,C. palustre, andC. vulgare, respectively. Survival was primarily explained by leaf trichome densities, and to a lesser extent by specific leaf area. Leaf flavonoid concentrations did not explain differences in beetle survival, and there were no differences in beetle weight gain or development time of individuals that survived to adulthood.4. No beetles survived on unshaved (hairy)C. vulgareplants, but manipulating leaf trichome densities of the thistle species by shaving the leaves moderated the plant‐specific resistance, and equalised the survival rates. Survival ofC. rubiginosaon alternative congeneric hosts was explained by a common physical resistance trait that varied in magnit

ISSN:0307-6946    

DOI:10.1111/een.12180

出版商:Blackwell Publishing Ltd    

年代:2015

数据来源: WILEY

摘要:

1. The performance of foliage feeders tends to decrease under elevatedCO2, but the responses of phloem‐feeding insects have been much more equivocal. As phloem tissues are less accessible than whole‐plant tissues, much less is known about how phloem composition is altered under elevatedCO2and the mechanisms driving changes in aphid performance.2. In this study, the plant mechanisms underlying the performance ofRhopalosiphum padiaphids onHordeum vulgare(barley) grown under ambient (390 ppm) and elevated (700 ppm)CO2were examined. We used aphid stylectomy to sample pure phloem from plants inCO2‐controlled conditions and high‐performance liquid chromatography to analyse phloem samples for amino acid concentrations.3. Aphid abundance significantly increased by 127% under elevatedCO2. Consequently, plant biomass decreased under elevatedCO2in trials with herbivores present, possibly due to the increased herbivore load, but increased when aphids were absent. The intrinsic rate of population increase (rm) was significantly higher under elevatedCO2; however, there were no statistically significant effects on aphid fecundity or development time. The concentration of individual amino acids tended to increase, although these increases were statistically significant in only a few cases. A principal components analysis revealed that the relative abundance (mol %) of those amino acids considered essential for aphids tended to increase under elevatedCO2.4. These results indicate thatCO2may affect nutrient translocation in plants in ways that are contrary to predictions about nitrogen metabolite responses toCO2. Such plant biochemical responses may underlie observations of improved phloem feeder performance under

ISSN:0307-6946    

DOI:10.1111/een.12181

出版商:Blackwell Publishing Ltd    

年代:2015

数据来源: WILEY

摘要:

1. It has become increasingly recognised that several herbivores switch from folivory (leaf‐feeding) to florivory (flower‐feeding) during larval development. Yet, it remains poorly understood which cues influence this behaviour, whether a switch to florivory is consistently shown on different hosts, and to what extent florivory could be hindered by plant traits.2. Using the sawflyAthalia rosaeand twoBrassicaceae differing in architecture and surface structure, the cues that influence larval movement to the flowers were investigated. A broad set of behavioural assays was employed and physical and chemical plant traits potentially affecting the larvae were analysed. Furthermore, the consequences of folivory versus florivory on insect performance were studied.3. The larvae preferred flowers over leaves. Consumption of particular flower parts correlated partly with measured plant traits such as glucosinolate distribution. Visual cues were of higher importance than volatile cues. The initial position of newly hatched larvae on plants influenced the probability of the larvae reaching the flowers during development. Trichomes and surface waxes hindered the larvae from moving upwards to the flowers. Larvae developed slower and gained less body mass when feeding on inflorescences ofBrassica nigrathan when feeding on leaves, in contrast to the patterns observed before onSinapis alba, where florivory led to an improved performance.4. This study demonstrates that florivory depends on various host plant traits. It reveals new insights into different parameters influencing this multifaceted phenomenon and into the expected impact on the ecology and fitness of both the attacking herbivores and the pla

ISSN:0307-6946    

DOI:10.1111/een.12182

出版商:Blackwell Publishing Ltd    

年代:2015

数据来源: WILEY

摘要:

1. Trichome‐producing (hairy) and trichomeless (glabrous) plants ofArabidopsis hallerisubsp.gemmiferawere investigated to test whether plant resistance to herbivory depends on the plants' phenotypes and/or the phenotypes of neighbouring plants (associational effects).2. A common garden experiment was conducted in which the relative frequency of hairy and glabrous plants was manipulated. Two species of leaf‐chewing insects (larvae of a white butterfly and a cabbage sawfly) were found less often on hairy plants than on glabrous plants. By contrast, the numbers of aphids and flea beetles did not differ significantly between hairy and glabrous plants. For none of these insects did abundance depend on the frequency of the two plant morphs.3. A field survey was conducted in two natural populations ofA. halleri. In the first population, a species of white butterfly was the dominant herbivore, and hairy plants incurred less leaf damage than glabrous plants across 2 years. By contrast, in the other population, where flea beetles were dominant, there were no consistent differences in leaf damage between the two types of plants. In neither of the two populations was any evidence found of associational effects.4. This study did not provide any conclusive evidence of associational effects of anti‐herbivore resistance, but it was discovered that trichomes can confer resistance to certain herbivores. Given the results of previous work by the authors on associational effects against a flightless leaf beetle, such associational effects of the trichome dimorphism ofA. halleriwere herbivore

ISSN:0307-6946    

DOI:10.1111/een.12179

出版商:Blackwell Publishing Ltd    

年代:2015

数据来源: WILEY

摘要:

1. Fig trees (Ficusspp.) and their host‐specific pollinator fig wasps (Agaonidae) are partners in an obligate mutualism. Receptive phase figs release specific volatiles to attract their pollinators, and this is generally effective in preventing pollinator species from entering figs of the wrong hosts.2. If entry is attempted into atypical host figs, then ostiole size and shape and style length may also prevent reproduction. In spite of these barriers, there is increasing evidence that fig wasps enter atypical hosts, and that this can result in hybrid seed and fig wasp offspring.3. This study examines the basis of pollinator specificity in two dioecious fig species from different geographical areas.Kradibia tentacularispollinatesFicus montanainAsia.Ficus asperifoliafromEastAfrica is closely related but is pollinated by a different species ofKradibia.4. In glasshouses,K. tentaculariswas attracted to its normal host,F1sand backcrosses, but only rarely entered figs ofF. asperifolia. Foundresses were able to lay eggs in hybrids, backcrosses, andF. asperifolia, although flower occupancy was lowest inF. asperifoliafigs and intermediate in hybrids.5. The fig wasp failed to reproduce in femaleF. montana,maleF. asperifolia, and maleF1s, and most but not all backcrosses toF. montana.This was a result of the failure to initiate gall production.6. Host specificity in this fig wasp is strongly influenced by host volatiles, but the ability to gall may be the ultimate determinant of whether it can reproduc

ISSN:0307-6946    

DOI:10.1111/een.12183

出版商:Blackwell Publishing Ltd    

年代:2015

数据来源: WILEY